Scilab Function
Last update : April 1993

predef - variable protection

### Calling Sequence

  `n=predef()`
  `oldnew=predef(n)`
  `oldnew=predef('all')`
  `oldnew=predef('clear')`

### Description

Utility function used for defining "oldest" variables as "protected". Protected variables cannot be killed. They are not saved by the `'save'` command. The "oldest" are those appearing last in the `who('get')`.

`predef()` gets the number of protected variables

`predef('a[ll]')` sets all the variables protected, it also return the old and new value of protected variables number.

`predef('c[lear]')` unprotect all but the last 7 variables, it also return the old and new value of protected variables number.

`predef(n)` sets the `max(n,7)` last defined variables as protected, it also return the old and new value of protected variables number.

### Remark

A number of protected variables are set in the start-up file `SCIDIR/scilab.star`. User may in particular set its own predefined variables in user's startup file `home/.scilab`

### See Also

`clear`, `save`,